Banggai Cardinals don't school as well as other species of Cardinalfish. As this species matures, they pair off for breeding purposes and then start to kill off other members of their group. Even if you find a group of them together at a store and they seem to be behaving, know that they will turn on each other until only two of them are left.

If you want a species that schools well, go for the Spotted Cardinalfish (Sphaeramia nematoptera). They're easy to care for, easy to find, and they don't use aggression to maintain the hierarchy of their group.